List of Articles

• Open Access Article
  • Abstract Page
  • Full-Text
  
  1 - Expert System Approach for Optimization of Design and Manufacturing Process for Rotary Ultrasonic Machining
  Morteza Sadegh Amalnik
  An expert system for evaluating rotary ultrasonic machining, in concurrent engineering environment and based on object oriented techniques, is developed. The design specification is obtained through a feature based approach. Different classes of design features are inte More

  An expert system for evaluating rotary ultrasonic machining, in concurrent engineering environment and based on object oriented techniques, is developed. The design specification is obtained through a feature based approach. Different classes of design features are interactively acquired. The attributes of different hard and brittle materials like glass, composite, stone and ceramic as work piece materials are stored in database. The system is also linked with tool material and machine databases. For each design feature, information is needed in manufacturing, such as machining cycle time, and cost, penetration rate, and efficiency are estimated by the expert system. Software system such as expert system based on object oriented technique is used to develop the expert system. The system links with a feature based CAD system in order to extract design data. The expert system provides useful information such as machining cycle time and cost, penetration rate, efficiency of machining of the selected design feature for product designers and advises of manufacturing engineers to select optimum machining parameters. In order to test the validity of the system, results of expert system is compared with the results of experimental rotary ultrasonic machining. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  2 - Analysis of Stresses in Tapered Rectangular Utility Pole
  Kondapalli Siva Prasad Chinthada Mankanteswar Rao
  Power transmission is generally carried out through electric cables supported by transmission pole (Utility pole) of various materials and cross sections. However, their utilization depends on climatic conditions and external loads acting on them. The forces comprise of More

  Power transmission is generally carried out through electric cables supported by transmission pole (Utility pole) of various materials and cross sections. However, their utilization depends on climatic conditions and external loads acting on them. The forces comprise of wind pressure, tension in conductors and seismic vibrations due to earthquakes. These loads induce various stresses in the pole like bending, shear, crushing etc. There is a necessity for investigation of these stresses in the existing utility pole subjected to the loads acting on them. The objective of the paper is to study the stresses developed in the tapered rectangular utility pole made of Steel Reinforced Concrete material which is 8m in total length. The work includes the calculation of stresses in the existing poles made of three grades of concrete (namely M40, M45, and M50), four different load cases of pre stressing (zero or no pre-stress, with a pre-stress of 50%, 60%, and 75% of maximum allowable strength of steel reinforcement), under the effect of 185 kmph wind velocity. Theoretical and FEA of stresses were carried out and the results were compared. The 3D solid modelling of pole is carried out using SOLIDWORKS and imported into ANSYS 15.0 for calculation of stresses. It is observed that in either cases of RCC and PSCC, the stresses developed in the concrete cause failure of the pole. However, in case of PSCC, the stresses causing failure are less compared to RCC and may have longer life. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  3 - Effect of Rotational Speed on Wear Behavior and Mechanical Properties of Friction Stir Welded AA6061+15%Al2O3p Metal-Matrix Composite
  Moslem Paidar Mojtaba Jafarian Mohsen Salehi Mohammad Saeed Khakpash
  The main objective of the present work was to investigate the effect of tool rotational speed on the mechanical and microstructural properties of aluminum based metal matrix composites (AA 6061 alloy reinforced with 15% of Al2O3 particles). The welds were produced by va More

  The main objective of the present work was to investigate the effect of tool rotational speed on the mechanical and microstructural properties of aluminum based metal matrix composites (AA 6061 alloy reinforced with 15% of Al2O3 particles). The welds were produced by varying the rotational speed from 630 to 1250 r/min while the chosen welding speed was 80 mm/min for analysis. It was found from the analysis of the microstructure that the changing of the rotational speed leads to variation of the grain size and also the fragmentation and improvement of Al2O3 particles distribution in nugget zone. Moreover, the obtained results clearly depicted that increasing rotational speed from 630 to 1250 r/min resulted in improvement of the wear resistance and also decreases the fluctuations of friction coefficient which can be attributed to the presence of Al2O3 particles which acted as barriers and restricted the grain growth in nugget zone. The lowest wear rate was achieved at welds produced at rotational speed of 1250 r/min. It was seen from the hardness results that the highest tensile strength value was obtained for 1250 r/min rotational speed with an average value of about 320 MPa (equivalent to 82% that of the base metal). Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  4 - Mechanical Behavior of Al-SiCnp Nanocomposite Fabricated by Hot Extrusion Technique
  A. Atrian S. H. Nourbakhsh
  In this paper, fabrication and characterization of Al-SiC nanocomposites is investigated. The Al matrix is reinforced with different amounts of SiC nano-particles using mechanical milling, cold pressing, and, hot extrusion techniques. To get the best quality of the samp More

  In this paper, fabrication and characterization of Al-SiC nanocomposites is investigated. The Al matrix is reinforced with different amounts of SiC nano-particles using mechanical milling, cold pressing, and, hot extrusion techniques. To get the best quality of the samples, the extrusion process is optimized firstly. With this regard, hot extrusion parameters such as the rate of extrusion, temperature, the extrusion ratio, lubrication, and the die set dimensions are experimentally studied. Finally, the nanocomposites with relative density more than 99% could be successfully fabricated under extrusion ratio of 8.5:1. As-extruded billets were then used to prepare standard tensile test specimens based on ASTM-E8. Afterwards, relative density, tensile behaviour, and micro-hardness of the samples were determined. The results show about 50% improvement for both the tensile strength and micro-hardness and near 1% reduction of relative density as the content of SiC reinforcement increases to 3 vol%. Therefore, specimens with higher strength-to-weight ratio which is a key parameter in aerospace and automotive applications can be produced using current techniques. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  5 - Preform and Process Design of Ti-6Al-4V Compressor Blade using Equipotential Lines and 3D FE Simulation
  M. Soleimanzadeh M.M. Fallah
  Forging is one of the most important processes for production of titanium parts. Selection and evolution of forging parameters such as the forging preforms, part and die temperatures and strain rate are of great importance to achieve optimal process. In this work, a com More

  Forging is one of the most important processes for production of titanium parts. Selection and evolution of forging parameters such as the forging preforms, part and die temperatures and strain rate are of great importance to achieve optimal process. In this work, a comprehensive study on the near net hot forging of a Ti-6Al-4V compressor blade is performed through designing several preforms and simulating the process in several die and preform temperatures. The Equipotential lines method is used for the optimal design of preforms and Johnson-Cook constitutive model is used for 3D FE simulations and the criteria for selecting the parameters was the material temperature during the process that is necessary for achieving desired properties of Ti-6Al-4V parts. According to the results, performing the isothermal forging process in increased speeds could lead to increasing the temperature over the β-transus and improper mechanical properties development. So, finding a proper die and preform temperature is necessarily accomplished in this work. According to results the appropriate temperatures for performing the process using modified 0.1v preform and ram speed of 1mm/s were 1050˚C and 450˚C for the preform and die respectively. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  6 - Finite Element Crushing Analysis, Neural Network Modelling and Multi-Objective Optimization of the Honeycomb Energy Absorbers
  M. Vakili M. Farahani A. Khalkhali
  The thin-walled honeycomb structures are one of the most common energy absorber types. These structures are of particular use in different industries due to their high energy absorption capability. In this article, the finite element simulation of honeycomb energy absor More

  The thin-walled honeycomb structures are one of the most common energy absorber types. These structures are of particular use in different industries due to their high energy absorption capability. In this article, the finite element simulation of honeycomb energy absorbers was accomplished in order to analyze their crushing behavior. 48 panels with different hexagonal edge length, thickness and branch angle were examined. In the following, the amounts of mean stresses versus the geometric variables using neurotic lattices were considered. Comparison between the finite element results and the obtained neural network model verified the high accuracy of the obtained model. Then the model was optimized by one of the efficient genetic algorithm methods called “Multi-objective Uniform-diversity Genetic algorithm”. The obtained optimum results provide practical information for the design and application of these energy absorbers regards to designer requirement. It was observed that honeycomb energy absorbers with 11.07 mm hexagonal edge length, 0.078 mm wall thickness and 123-degree branch angle have the maximum energy absorption over the panel mass. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  7 - Transient Analysis of Heat and Mass Transfer via Natural Convection over a Vertical Complex Wavy Surface
  Morteza Ghadimi Amir Lotfi Cyrus Aghanajafi
  A numerical study of transient natural convection heat and mass transfer along a vertical complex wavy surface has been performed. A complex wavy surface was created from two sinusoidal functions, a fundamental wave and its first harmonic. The complex wavy surface is ma More

  A numerical study of transient natural convection heat and mass transfer along a vertical complex wavy surface has been performed. A complex wavy surface was created from two sinusoidal functions, a fundamental wave and its first harmonic. The complex wavy surface is maintained at uniform wall temperature and constant wall concentration. An implicit finite-difference scheme is used for analysis. The numerical results demonstrate that the additional harmonic substantially alters the flow field, temperature and concentration distribution near the surface. Also the numerical results show that the local heat and mass transfer rate for a complex surface are smaller than of a flat plate. This decreased local heat and mass transfer rate seems to depend on the ratio of amplitude surface. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  8 - Reliability and limitations of Impact-Echo Method for Thickness Measurement of Orthotropic Composite Plates
  M. Amiri M. Tabatabaee Ghomi Gh. Liaghat
  In this paper, an Impact-Echo method has been used to numerically simulate low velocity impact of a steel ball on laminated composite plates in order to measure the plate's thickness. For the purpose of simulation, Ls-Dyna finite element code has been employed to expres More

  In this paper, an Impact-Echo method has been used to numerically simulate low velocity impact of a steel ball on laminated composite plates in order to measure the plate's thickness. For the purpose of simulation, Ls-Dyna finite element code has been employed to express the behaviour of impact between steel ball and composite plates. Furthermore, a single node near the impact area has been chosen and its displacement was demonstrated during the impact time on a graph by the software. After that, displacement-time graph was transformed to amplitude-frequency domain graph by means of Fast Fourier Transform which was done by MATLAB software. The peak frequency was used to calculate the plate's thickness. The calculated thickness was verified by real plate thicknesses and this comparison shows an acceptable agreement between simulation and experimental results. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  9 - Effect of Non-Newtonian Models on Blood Flow in Artery with Different Consecutive Stenosis
  Mehdi Jahangiri Ahmad Haghani Reza Ghaderi Seyyed Mohammad Hosseini Harat
  In this paper, the ADINA finite element software was used for numerical investigation of laminar and non-Newtonian flow through a blood artery with consecutive stenosis. For modeling the non-Newtonian behavior of blood, six models were used, namely, Carreau, Carreau-Yas More

  In this paper, the ADINA finite element software was used for numerical investigation of laminar and non-Newtonian flow through a blood artery with consecutive stenosis. For modeling the non-Newtonian behavior of blood, six models were used, namely, Carreau, Carreau-Yasuda, modified Casson, Power law, generalized power law, and Walburn-Schneck. The results show that for all non-Newtonian models as well as the Newtonian model, the velocity of blood flow in the second stenosis is greater than the first stenosis. Also, up to 4D back of second stenosis, a reverse flow area is formed that causes the spread of disease and the formation of new plaque. As a general conclusion, it can be stated that due to the smaller values obtained from the power law and Walburn-Schneck models, as compared with the other models, for fluid velocity and wall shear stress, these two models must be applied with caution. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  10 - Corrosion Behavior Characterization of the Nugget Zone in Copper/Brass Metals of Dissimilar Friction Stir Welded Lap Joints
  kamran amini Farhad Gharavi
  The electrochemical behavior of the weld nugget zone (WNZ) in copper-brass plates was studied in this paper. These plates were welded by the friction stir lap welding method in 1M NaCl solution at low heating input (450 rpm-25 mm/min ) and high heating input (710 rpm-16 More

  The electrochemical behavior of the weld nugget zone (WNZ) in copper-brass plates was studied in this paper. These plates were welded by the friction stir lap welding method in 1M NaCl solution at low heating input (450 rpm-25 mm/min ) and high heating input (710 rpm-16 mm/min) by using the electrochemical impedance spectroscopy (EIS) and Tafel polarization at ambient temperature. The morphology of nugget zone corroded surfaces was analyzed by SEM (scanning electron microscopy) technique. The welding process appeared to decrease the corrosion resistance of the welded nugget regions through increasing the welding heat input. The results from EIS measurements presented the welded joints of NZ which showed higher and lower values respectively than brass and copper. Due to changing of microstructural of weld nugget zone during welding process, the Icorr of nugget zone enhances with increasing welding heat input. In fact, the surface corrosion morphology analysis revealed that the surface of welded sample by high heating input was shielded with a roughly porous corrosion layer rather than the surface of the welded sample at low heating input Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  11 - Determining Position and Orientation of 6R Robot using Image Processing
  Amin Habibnejad Korayem Ensieh Niyavarani Saeed Rafee Nekoo Moharam Habibnejad
  Stereo vision is one of the best image processing softwares to identify the environment of robot and allow its simultaneous process for providing three-dimensional measurement in an acceptable rate. On the one hand, vision measurement has simple structure and on the oth More

  Stereo vision is one of the best image processing softwares to identify the environment of robot and allow its simultaneous process for providing three-dimensional measurement in an acceptable rate. On the one hand, vision measurement has simple structure and on the other hand it is independent from active machine or robot. Appropriate software and efficient programming could improve the performance with same hardware (cameras). In this paper, stereo vision robot localization is used and the main code was developed in open source computer vision (Open CV) environment. The mathematical relationship between the three-dimensional reference coordinates and the local coordinates for entire system are presented. The vision system is an independent unit consists of two high definition (HD) cameras, set in a rotary base. The application of this measurement provides the position and orientation of 6R robot to verify its current measurement system. Stereo vision improved the speed of the image processing in comparison with image processing of MATLAB Toolbox that led to online monitoring of trajectory. Experimental tests of the proposed method express the capability of stereo vision in practical operations as a supervisory section. Manuscript profile